This paper investigates the latency and resilience of user-plane anchor reconfiguration in a fully virtualized 5G core environment using Open5GS and UERANSIM. The experiment spans five VirtualBox virtual machines, each hosting a key component of the 5G core or radio stack: 5G-core gNB, UPF1, UPF2, and a single UE. All nodes communicate over a shared internal network, ensuring controland user-plane traffic remains isolated from external variability. The UE is initially anchored to UPF 1 via DNN “internet.” After the initial tunnel is established and validated, a re-anchoring procedure is triggered by calling the SMF’s REST API. Although the endpoint is intended to perform a PFCP Session Modification, Open5GS tears down the session and creates a new one on UPF 2 instead. By analyzing timestamped UE logs—capturing tunnel setup, session release, and re-establishment—we measure the latency of user-plane reattachment. Our results reveal high variability in recovery times, ranging from sub-second to over 50 seconds. These inconsistencies are attributed to limitations in Open5GS’s session handling, the lack of true migration support, and hardware limitations of the used machine. Despite these challenges, the study offers insights into the practical behavior of PFCP-driven anchor reconfiguration and the operational gaps that remain in open-source 5G core implementations.